#include "chunk.h"

Chunk::Chunk(int x, int y) : m_posX(x), m_posY(y) { m_blocks.Reset(BTYPE_AIR); }

Chunk::~Chunk() { }

void Chunk::RemoveBlock(int x, int y, int z) {
    m_blocks.Set(x, y, z, BTYPE_AIR);
    m_isDirty = true;
}

void Chunk::SetBlock(int x, int y, int z, BlockType type) {
    m_blocks.Set(x, y, z, type);
    m_isDirty = true;
}

BlockType Chunk::GetBlock(int x, int y, int z) { return m_blocks.Get(x, y, z); }

void Chunk::Update(BlockInfo* blockinfo[BTYPE_LAST]) {
    float u, v, s;
    // Update mesh
    if (m_isDirty) {
        int maxVertexCount = (CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z) * (6 * 4);
        VertexBuffer::VertexData* vd = new VertexBuffer::VertexData[maxVertexCount];
        int count = 0;
        for (int x = 0; x < CHUNK_SIZE_X; ++x) {
            for (int z = 0; z < CHUNK_SIZE_Z; ++z) {
                for (int y = 0; y < CHUNK_SIZE_Y; ++y) {
                    if (count > USHRT_MAX)
                        break;
                    BlockType bt = GetBlock(x, y, z);
                    if (bt != BTYPE_AIR) {
                        blockinfo[bt]->GetTexture(u, v, s);
                        AddBlockToMesh(vd, count, bt, x, y, z, u, v, s);
                    }
                }
            }
        }
        if (count > USHRT_MAX) {
            count = USHRT_MAX;
            std::cout << "[ Chunk :: Update ] Chunk data truncaned , too much vertices to have a 16 bit index " << std::endl;
        }
        m_vertexBuffer.SetMeshData(vd, count);
        delete[] vd;
    }
    m_isDirty = false;
}

void Chunk::AddBlockToMesh(VertexBuffer::VertexData* vd, int& count, BlockType bt, 
                           int x, int y, int z, float u, float v, float s) {
    
    if (x == CHUNK_SIZE_X - 1 || GetBlock(x + 1, y, z) == BTYPE_AIR) {                      //  x
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z, .9f, .9f, .9f, u, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, .9f, .9f, .9f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, .9f, .9f, .9f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, .9f, .9f, .9f, u + s, v);
    }

    if (x == 0 || GetBlock(x - 1, y, z) == BTYPE_AIR) {                                     // -x
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, .9f, .9f, .9f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, .9f, .9f, .9f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y, z, .9f, .9f, .9f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, .9f, .9f, .9f, u, v);
    }

    if (y == CHUNK_SIZE_Y - 1 || GetBlock(x, y + 1, z) == BTYPE_AIR) {                      //  y
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, .8f, .8f, .8f, u, v);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, .8f, .8f, .8f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, .8f, .8f, .8f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, .8f, .8f, .8f, u + s, v);
    }

    if (y == 0 || GetBlock(x, y - 1, z) == BTYPE_AIR) {                                     // -y
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, .8f, .8f, .8f, u, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z, .8f, .8f, .8f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z, .8f, .8f, .8f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, .8f, .8f, .8f, u + s, v);
    }

    if (z == CHUNK_SIZE_Z - 1 || GetBlock(x, y, z + 1) == BTYPE_AIR) {                      //  z
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, 1.f, 1.f, 1.f, u, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, 1.f, 1.f, 1.f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, 1.f, 1.f, 1.f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, 1.f, 1.f, 1.f, u, v + s);
    }

    if (z == 0 || GetBlock(x, y, z - 1) == BTYPE_AIR) {                                     // -z
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, 1.f, 1.f, 1.f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, 1.f, 1.f, 1.f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z, 1.f, 1.f, 1.f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z, 1.f, 1.f, 1.f, u, v);
    }
}

void Chunk::Render() const { m_vertexBuffer.Render(); }

bool Chunk::IsDirty() const { return m_isDirty; }